Module documentation for 0.4.6.1

transient-universe is the distributed computing extension of transient and uses transient primitives heavily for parsing, threading, event handling, exception handling, messaging etc. It support moving computations between Haskell closures in different computers in the network. Even among different architectures: Linux nodes can work with windows and browser nodes running haskell compiled with ghcjs.

The primitives that perform the moving of computations are called wormhole and teleport, the names express the semantics. Hence the name of the package.

All the nodes run the same program compiled for different architectures. It defines a Cloud computation (monad). It is a thin layer on top of transient with additional primitives and services that run a single program in one or many nodes.

Browser integration

Browser nodes, running transient programs compiled with ghcjs are integrated with server nodes, using websockets for communication. Just compile the program with ghcjs and point the browser to http://server:port. The server nodes have a HTTP server that will send the compiled program to the browser.

Distributed Browser/server Widgets

Browser nodes can integrate a reactive client side library based in trasient (package axiom). These widgets can create widgets with HTML form elements and control the server nodes. A computation can move from browser to server and back despite the different architecture.

Widgets with code running in browser and servers can compose with other widgets. A Browser node can gain access to many server nodes trough the server that delivered the web application.

These features can make transient ideal for client as well as server side-driven applications, whenever distribution and push-driven reactivity is necessary either in the servers or in the browser clients.

New

The last release add

Hooks for secure communications: with transient-universe-tls package, a node can use TLS to connect with other nodes, including web nodes. If the connection of a web node is initiated with “https” the websocket connection uses secure communications (wss). The only primitive added is initTLS.

Client websocket connections to connect with nodes within firewalled servers: a server node can connect with another situated after a HTTP server. All the process is transparent and add no new primitive; First connect tries a TCP socket connection if it receives other message than “OK”, it tries a connection as a websocket client. This is important for P2P connections where a central server acts as coordinator. websocket connections can use TLS communications too.

No network traffic when a node invokes itself

Map-reduce

transient-universe implements map-reduce in the style of spark as a particular case. It is at the same time a hard test of the distributed primitives since it involves a complex choreography of movement of computations. It supports in memory operations and caching. Resilience (restart from the last checkpoint in case of failure) is not implemented but it is foreseen.